Comparison of two handheld applanation tonometers and the association of central corneal thickness, age, and intraocular pressure in normal and diseased canine eyes

Abstract

The AccuPen(®) measurements were slightly but significantly lower than the Tono-Pen XL(®) measurements in both normal and diseased canine eyes. The CCT affected the results of neither tonometer regardless of disease, while both IOP and CCT tended to decrease with age in normal eyes.

Measurement of intraocular pressure in clinically normal Turkish Shepherd Dogs with the rebound tonometer (TonoVet®) and the applanation tonometer (Tono-Pen Vet®)

“…Former clinical trials using two different applanation tonometers in dogs determined that IOP tended to decrease with age (7,13). Similar results were obtained in a study on Anatolian buffaloes (28).…”

“…The statistical evaluation showed no difference between the means for the two age groups obtained by both devices. The present study, along with others (22-24), does not confirm the reports that IOP significantly changes with age (7,13,28). In our literature review, except for a study on humans (37) and a study on lions (24), none of recent studies (22,23,25,30,36) has reported a significant relationship between the sex variable and IOP.…”

Diurnal variations in intraocular pressure and central corneal thickness and the correlation between these factors in dogs

“…The effect exerted by CCT on IOP was found to differ between the TonoPen XL and TonoVet tonometers, and IOP values were shown to increase by 1 and 2 mmHg, respectively, for every 100 μm increase in CCT . However, other studies have found no correlation between CCT and IOP in dogs …”

Design of an intraocular pressure curve protocol for use in dogs

“…One study demonstrated that for every 100µm increase in central corneal thickness in normal dogs there was an elevation of 1mmHg in IOP using applanation tonometry (Park et al 2011). However, another study demonstrated that central corneal thickness did not affect applanation tonometry (Kato 2014). Other viscoelastic properties of the cornea such as corneal hysteresis and corneal resistance factor can also alter IOP readings in humans (Liu and Roberts 2005).…”